So, I appreciate the idea that you're aiming for, but there's quite a few flaws with the deck you posted.
Deck Colors: You don't have to play three colors. Currently you have white for [[Ojutai's Command]], [[Dromoka's Command]], and two creatures ([[Reflector Mage]] and [[Eldrazi Displacer]]). Considering the mana color issues the deck already has, it might be worthwhile to look at other replacements for those cards and drop white. For example, [[Vile Redeemer]] is right up your alley and can help you rebuild from a lost board state. [[Icefeather Aven]] can lead to some insane tempo plays, as can [[Bounding Krasis]] (Though you seem to dislike him).
That being said, UG is arguably one of the weakest color combinations currently. It might be worth it to move white to red for the Temur support cards (like [[Savage Knuckleblade]] and [[Termur Charm]]) and some of the removal red offers (like [[Fiery Impulse]], [[Rending Volley]], and [[Roast]]).
The Idea: Flash is interesting. It's a great mechanic when it's convenient or coupled with an strong upside or ability (see [[Snapcaster Mage]] and [[Mystic Snake]]). Unfortunately, I don't think that support/cards are in these sets. What you end up with is a deck that leans heavily on holding up mana to try and force the gimmick of flash to it's advantage. Instead, the first time an opponent lands something big that sticks (any decent planeswalker for example), you're in a really tough spot. And instead of having a toolkit of answers, you have counters and a few tricks to hopefully get things back into their owner's hand so you can deal with them later.
Now, am I right? Should you change your deck? I don't honestly know. You gave us no inclination to the testing you've done with this. There are many different sources of practice available (namely either proxying or programs like Cockatrice). You might have enough tempo to win for all I know. I'm just some dude behind a keyboard trying to hand you my two cents. Hopefully though, this will give you insight as to possible weaknesses in your deck and might help you tighten up the deck or shift it's path to make it more consistent and powerful.